Journal article
Investigation of top electrode for PZT thick films based MEMS sensors
Department of Micro- and Nanotechnology, Technical University of Denmark1
Silicon Microtechnology Group, MicroElectroMechanical Systems Section, Department of Micro- and Nanotechnology, Technical University of Denmark2
MicroElectroMechanical Systems Section, Department of Micro- and Nanotechnology, Technical University of Denmark3
Ferroperm A/S4
Meggitt A/S5
In this work processing of screen printed piezoelectric PZT thick films on silicon substrates is investigated for use in future MEMS devices. E-beam evaporated Al and Pt are patterned on PZT as a top electrode using a lift-off process with a line width down to 3 mu m. Three test structures are used to investigate the optimal thickness of the top electrode, the degradation of the piezoelectric properties of the PZT film in absence of a diffusion barrier layer and finally how to fabricate electrical interconnects down the edge of the PZT thick film.
The roughness of the PZT is found to have a strong influence on the conductance of the top electrode influencing the optimal top electrode thickness. A 100 nm thick top electrode on the PZT thick film with a surface roughness of 273 nm has a 4.5 times higher resistance compared to a similar wire on a planar SiO2 surface which has a surface roughness of less than 10 nm.
It is found that the piezoelectric properties of the PZT thick film are degraded up to 1,000 mu m away from a region of the PZT thick film that is exposed directly to the silicon substrate without a diffusion barrier layer. Finally, ferroelectric hysteresis loops are used to verify that the piezoelectric properties of the PZT thick film are unchanged after the processing of the top electrode.
Language: | English |
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Publisher: | Springer US |
Year: | 2010 |
Pages: | 150-158 |
ISSN: | 15738663 and 13853449 |
Types: | Journal article |
DOI: | 10.1007/s10832-010-9606-7 |
ORCIDs: | Pedersen, Thomas and Thomsen, Erik Vilain |